5.3 Adding and Subtracting Mixed Numbers

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5.3 Adding and Subtracting Mixed Numbers

• I can add and subtract mixed numbers with unlike
  denominators

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Additional Example 1A Adding and Subtracting
Mixed Numbers Find the sum. Write the answer in
simplest form.
3 1
3 2 5
Estimate the sum.
Multiply the denominators. 8 6 48
3
3
Write equivalent fractions with a denominator of
48.
1
1
______ ______
Add the fractions and then whole numbers, and
simplify.
4 4
3
Check It Out Example 1C Find the difference.
Write the answer in simplest form.
7 2
8 2 6
Estimate the difference.
Think 8 is a multiple of 4, so 8 is the LCD.

7
7
Write equivalent fractions with a denominator of
8.
2
2
______ ______
Subtract the fractions and then the whole
numbers.
5
5 is close to the estimate 6. The answer is
reasonable.
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Additional Example 2 Measurement Application The
length of Jens kittens body is 10 inches.
Its tail is 5 inches long. What is the total
length of its body and tail?
Find a common denominator. Write equivalent
fractions with the LCD, 8, as the denominator.

10
10
5
5
______ ______
Add the fractions and then the whole numbers.

15
The total length of the kittens body and tail is
15 inches.
5
Check It Out Example 2 The length of Reginas
mouses body is 2 inches. Its tail is 2
inches long. What is the total length of its
body and tail?
Find a common denominator. Write equivalent
fractions with the LCD, 6, as the denominator.

2
2
2
2
______ ______
Add the fractions and then the whole numbers.

4
The total length of the mouses body and tail is
4 inches.
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Lesson Quiz
Find each sum or difference. Write the answer in
simplest form. 1. 2. 3.
4. 5. Miles worked 5 hours on Friday
and 8 hours on Saturday. How many total
hours did he work?
3
2
__
__
3
4
14 hours